1. Field of Invention
The present invention relates to apparatuses and methods for monitoring, measuring, or analyzing changes in the volume and/or density of solid and/or fluid samples.
2. Description of Prior Art
In many industrial environments—including but not limited to the drilling of oil and geothermal wells—the use of fluids under high temperature and high pressure conditions is commonplace. Understanding and predicting the changes of said fluids under said conditions can be vital to their efficient and safe use; in particular, changes of their density or specific volume.
Devices that can be found within the marketplace that are capable of resolving changes of specific volume are densitometers, pycnometers, dilatometers, pressure-volume-temperature (pvT) devices, etc.
U.S. Pat. No. 6,718,281 describes a dilatometer that can measure volume changes of liquid and solid samples. However, it possesses multiple disadvantages such as excessively complicated mechanical structure, usage of highly dangerous and toxic mercury, the fact that it is not capable of being pressurized to very high pressure due to its optical components, etc. These disadvantages prevent it from being used to monitor fluid and solid density changes under simulated drilling conditions.
Other devices which are used to measure the volume change of fluids, such as the pycnometer shown in U.S. Pat. No. 3,129,585, use mechanical indicators to measure the density change of a fluid, without the capability of recording data. Also, in FIG. 1 of U.S. Pat. No. 3,129,585, the movement of piston 14 has to be mechanically transferred to the outside of a pressurized chamber through a seal. This would induce measurement errors and introduce difficulty in sealing when pressure is above 10,000 psi.
It is an object of this invention to provide a means for testing liquid density changes under simulated downhole conditions in deep oil or geothermal wells.
It is a further object of this invention to provide a means for testing the volumetric expansion or contraction of a solid sample under varying and controllable conditions of temperature and pressure without contamination by pressurization fluid.
It is a further object of this invention to provide a means for automatically tracking and recording said changes in sample volume.
It is another object of this invention to provide a densitometer which does not require the use of any specific fluid of any toxicity whatsoever.
It is another object of this invention to provide a specific volume measurement device which requires substantially less maintenance work than other designs yet meets industry standards of accuracy, reliability, durability, dependability, and ease of cleaning.